@one
We do not live in an ideal world, in your example with cryptocurrencies you can see how to appear an infinite number of incompatible solutions.
XMPP has the goal of unifying all instant messengers, XMPP is not a messenger.
The matrix may be part of the XMPP, but the developers of the Matrix refused it.
The matrix will not be able to raise money if it becomes a real federation. When one super server and one super client, it is easier to convince investors that they are cool.